/Engine/Source/Runtime/ApplicationCore/Public/Null/NullWindow.h
Populates the size and location of the window when it is restored. If the function fails, false is returned and X,Y,Width,Height will be undefined.
true when the size and location and successfully retrieved; false otherwise.
virtual bool GetRestoredDimensions ( int32 & X, int32 & Y, int32 & Width, int32 & Height )